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| java.lang.Object
 org.jfree.report.function.AbstractExpression
org.jfree.report.modules.misc.beanshell.BSHExpression
| BSHExpression | | public class BSHExpression extends AbstractExpression (Code) | | An expression that uses the BeanShell scripting framework to perform a scripted
calculation. The expression itself is contained in a function called
Object getValue()
and this function is defined in the expression property. You have to
overwrite the function getValue() to begin and to end your expression, but
you are free to add your own functions to the script.
By default, base Java core and extension packages are imported for you. They are:
java.lang java.io java.util
java.net java.awt java.awt.event
javax.swing javax.swing.event
An example in the XML format: (from report1.xml)
// you may import packages and classes or use the fully qualified name of the class
import org.jfree.report.*;
String userdefinedFunction (String parameter, Date date)
{
return parameter + " - the current date is " + date);
}
// use simple java code to perform the expression. You may use all classes
// available in your classpath as if you write "real" java code in your favourite
// IDE.
// See the www.beanshell.org site for more information ...
//
// A return value of type "Object" is alway implied ...
getValue ()
{
return userdefinedFunction ("Hello World :) ", new Date());
}
author:
Thomas Morgner |
| Field Summary | |
| final public static String | BSHHEADERFILE
The headerfile with the default initialisations. |
| Constructor Summary | |
| public | BSHExpression()
default constructor, create a new BeanShellExpression. |
| Method Summary | |
| protected Interpreter | createInterpreter()
This method tries to create a new and fully initialized BeanShell interpreter. | | public String | getExpression()
Sets the beanshell script as string. | | public Expression | getInstance()
Return a new instance of this expression. | | public Object | getValue()
Evaluates the defined expression. | | protected void | initializeInterpreter(Interpreter interpreter)
Initializes the bean-shell interpreter by executing the code in
the BSHExpressionHeader.txt file. | | public void | setExpression(String expression)
Sets the beanshell script that should be executed. |
| BSHHEADERFILE | | final public static String BSHHEADERFILE(Code) | | The headerfile with the default initialisations.
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| BSHExpression | | public BSHExpression()(Code) | | default constructor, create a new BeanShellExpression.
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| createInterpreter | | protected Interpreter createInterpreter()(Code) | | This method tries to create a new and fully initialized BeanShell interpreter.
the interpreter or null, if there was no way to create the interpreter. |
| getExpression | | public String getExpression()(Code) | | Sets the beanshell script as string.
the script. |
| getInstance | | public Expression getInstance()(Code) | | Return a new instance of this expression. The copy is initialized and uses the same
parameters as the original, but does not share any objects.
a copy of this function. |
| getValue | | public Object getValue()(Code) | | Evaluates the defined expression. If an exception or an evaluation error occures, the
evaluation returns null and the error is logged. The current datarow and a copy of
the expressions properties are set to script-internal variables. Changes to the
properties will not alter the expressions original properties and will be lost when
the evaluation is finished.
Expressions do not maintain a state and no assumptions about the order of evaluation
can be made.
the evaluated value or null. |
| initializeInterpreter | | protected void initializeInterpreter(Interpreter interpreter) throws EvalError, IOException(Code) | | Initializes the bean-shell interpreter by executing the code in
the BSHExpressionHeader.txt file.
Parameters:
interpreter - the interpreter that should be initialized.
throws:
EvalError - if an BeanShell-Error occured.
throws:
IOException - if the beanshell file could not be read. |
| setExpression | | public void setExpression(String expression)(Code) | | Sets the beanshell script that should be executed. The script should
define a getValue() method which returns a single object.
Parameters:
expression - the script. |
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